Blood poisoning red line: what should you know?

A line extending away from a cut, bite or other wound may follow inflammation in lymphatic vessels. It can occur with Cellulitis, which commonly causes redness, warmth, swelling and tenderness around the entry point. A red line does not by itself diagnose blood poisoning, but it is a reason to arrange urgent review. Fever, Chills, Feeling Generally Unwell or Generalised Weakness may suggest that infection is affecting more of the body. Sepsis is a medical emergency involving a dangerous body-wide response.

Mark the outer edge of redness with a pen and write down the time; this can help a clinician judge whether it is spreading. Gently clean and cover the wound, keep the area elevated if comfortable, and avoid squeezing, cutting or applying irritating substances. Do not share or use leftover antibiotics. Take a clear photo if useful, but do not delay assessment while monitoring it.

Get same-day medical assessment for any red line that is extending, painful or associated with a wound. Call emergency services for confusion, fainting, breathing difficulty, severe weakness, rapidly worsening pain, very pale or clammy skin, or inability to stay awake. Fever or chills with a spreading line should be treated as urgent, particularly in someone with diabetes, poor circulation or reduced immunity.

Ask whether the line is lymphatic inflammation or another skin change, how deep the infection may be, and whether treatment should start immediately. Tell the clinician how the wound happened, when the line appeared, how fast it changed and whether you have fever or weakness.